Method of and apparatus for measuring the flow of fluids



Jun 24, 1930. c. s. II=INKERTON METHOD OF AND" APPARAIUS FOR MEASURING THE FLOW OF FLUIDS Filed Aug. 28, 1925 INVIIZNTOR I A TTORNE Y Patented June 24, 1930 i i cLAnn cE s. rIiIKEnroN, or I WAUKEE, w 'scori's'rmlassreuos; BY missus 'i issi( n r- I Mmrrs, TO 'cvr nn-xm vrmnafmc, A ooaroaarror or DE WAR i g i MEIHQD or 1ND; ArrAanrUs For; MEASURING 'rr-rn rtowor'rrurijs j r v c Application *fiiei {August 28, 1925; Serial m; 53,040.

This invention relatesto improvements'in methods of and apparatus for measuring the flow of :fluids. Morepar'ticularly the invention-relates to meters of "the type disclosed in the patent ofJQC. Wilson, No. 1,61 l,7O2,

dated January-'18, 1 927. r,

'Meters'of the type disclosed the 'aforementioned patent comprise in generalmeans for circulating a liquidior fluid medium in heatexchangingrelation with the fluid to be measured, 'means -for "utilizir ig theitemperature change of this medium in determining-the rate of flow, means for utilizingthe quantity of such mediumin determiningthe rate :of flow, and means'for utilizing the temperature change of the fluidto be measuredin'determining the rate of flow.

I An object of the invention 'is toisimplify meters of the aforementioned character,

Another object, is to obviate the necessity for measuring or maintaining'constant cer- 1 min of the factors involvedinvthe heatjeX- 'change V Another object is to provide for maintain factors.

' c Another and "fluid to be measured. 1

ing: a constant ratio between certain of said more specific object is to provide for maintainmg a constant ratiob'ee tween the temperature change of'the fluid edium and the temperature change of the Another object is toprovide rate of flow of 'the fluid m'edium'may'be utilized asa direct indicationof the rate of.

flow of the fluid being measured; 7 v Other, objects and. advantages ofv thein- "vention' will hereinafter 'appear. Y

The accompanying drawing. illustrates schematically and diagrammatically one em- 'bodiment of the invention and the'same will now be described, it being understood that the embodimentillustrated is. susceptible of or other fluid tobemeasured is adapted to flow in the direction indicated bythe' arrow.

Located within the conduit 5, is a coiled tube tively', at opposite ends of thefcoil 6. The I 1 inlet thermometer; resistances T and t are i for maintain- I in'g the aforementioned ratio whereby the wh between the pairsof .resistanc'est T and T tr" to provide for initially balancing the bridge,

electrical energy, as indicated'by, lines Ll, L Connected across the W'heatstone bridge is a control galvanometer G of usual construct ion, said galvanometerchaving a-movg able conducting element 19. The element 19 is shovvnxin'the' position it normally assumes} nace air,"due to its pressurev of twelve to fifteen pounds; is alwayssuperheated to a v. temperature of about 150m, 225; degrees F.,

and hence it'is possible toymeasure this air by a coollng method without encountering any CllfilCHltlQS-Cllle to condensation ofmoistrue on the cooling device. The tube 6 is therefore preferably supplied froma suitablesource of cooling water through pipes YS and 9, ajneedle valve 10 being provided for varying the rate of flow of. water through said tube, as hereinafter described. The Water is adapted to discharge from tube-6 through a pipe 12, said pipe having associ- 7' ated therewith a diiferential fluid meter l3 I comprising-2a U-tubelt containinga body of liquid. and having'the respective legs com municating, as indicated at l5-and' 16, with 'oppositevendsl of a Venturi tube 17 orthei like. Also associated with 7 pipe 12 .is-an integratlng fluid meter '18.

Located within the conduit that opposite sides. of the coil 6 are thermometerresistances T and T ,nr espectively, Whereas thermometer resistancesat Q and t are likewise located withinthe pipes 9.and l2,"resp'ec-- connected in series to form, onelegof a 'Wheatstone bridge, whereas the outlet'thermometer resistances. T and t are similarly ing two legs thereof, in theusual manner, ereas a variable resistance R- 18 provlded as hereinafter 1 described. The Wheatstonebndge circuit is connected in the usual manner with azsuitable source of when the Wheatstone bridge vis'inbal'anced 1 condition, whereas upon unbalancing of the 7 bridge in one direction said element is moved into a position to be clamped-between the stationary contact 19? and theintermittently movable contact19 thus providing an enere .gizing circuit for the winding '22 of a sole I noi'd operated pawl23 which circuit may be traced. from line Liby conductors 20. and

20 throughcontact 19 element :19 and con.-

tact'19, byconductor 21 tliroi gliwvinding 22, and by conductors 24 and 25, to line D.

1 Operation of pawl 23 effects movement of a. r ratchet wheel 27 which is secured to the stem 28 of'needle valve10, thus effecting opening movement of the latter bycooperation of the threaded portion 29 'of its stemwitha threadedop'ening in the valve chamber. 6 The resulting increased flow of waterthrough coil 6 is adapted to effect re-ba lancing of the VVheatstone bridge When unbalancing of thebridgeis of an opposite value, element'19 is adapted to move intov aposition tojbe clamped between the stationary contact 19 and the intermittentlymovablecontact 19,

to complete an-energizing circuit for winding 31 of a solenoid operated pawl32 to et-' feet movement of valve stem 28 in the oppo site direction through ratchet'wheel 33, thus effecting closing movement of valve 10. The energ-izmgicircuit for winding 31. may be traced'from line: L2,.by conductors and 20 through contact 19 element '19 and contact 19 by conductor through said wind I mg, and, by conductors 34 and 25 to line L Any suitable means may be provided foreifecting such intermittent movement of con tacts l9 and 1.9,"whereasi1 have shown for v this purpose a moto'r'M connected across lines'L L and adapted to effect operation of said contacts'throu'gh' suitablereduction gearing. and anfeccentric 35.

I preferably provide means for by-passmg -the coil 6 to facilitate initial balancing of i Q45. V

' ing'a valve 36-whichis adapted to be closed the VVheatstone bridge,said means'comprisr for preventing; passage of the water through coil 6, and aby-pass pipe 37 having a valve 38 which is adapted when open to permit assa e .ot the water from .pi e9jthrou h P e P g pipe 37 to pipe 12. It will of course be understood that by-pass pipe is located outside'of conduit 5. I, V 7

With the coil 6 by-passed' as aforedescribed, the thermometer resistances T and T will each attain the normal temperature otthe blast furnace air, whereas the thermometer resistances t? and t will-each attain the normal temperature of the water, and

the lVheatstone bridge may obviously be balanced by .manipulation of the irheostat 'R. Thereafter.thejvalve 361is opened'and the valve 38 closed, thus effecting. passage of the cooling water'through coil6 in heat exchanging relation with the 2111. passing through conduit 5; Assuming a constant basic temperature of th'e air flowing in con- .duit 5, if too little water is flowing through coil 6 the combined values of the thermal effects on resistances Z and'T will be high-,-

er than the combined values of the thermal effects on resistances t andT thereby unbalancing the bridge circuit and causing a position to bridge contacts19 and 19 as .aforedescribed, to eil'ectopening movement of the needle valve 10; which opening movefmov'ement of galvanometer element 19 into i inent will continue "until s'ufiicient water is flowin g to bring the thermometer resistances t? and T down to a'temperature. such that the combined values oftliethermometer :re-

.the; combined values thereof are equal to sistances t andl The. bridge circuit will thus be again balanced, thereby indicating attamment of a predeterminedrelat on=or ratio between the temperature rise or the water and the temperature-drop ofthe air,

due to the heat exchangeyand the device will automatically 'maintainxthis ratio. .The

ratio aforementioned will of course depend I upon the physical characteristics (such as specific heat: or heat capacitylor" the'fluids V v between which the heat exchange takes place. Thus, the .metercould be operated i with an ail-temperature drop of, say, .10

which would tend to minimize 7 degrees R,

the effect of balance shifts encountered when a lesser temperature drop v is employed; whereas the water could be run at-a temperature rise of about 50 degrees "Fr cu. it;standard cubic feet of air per hour. ht. cap.=heat air.

sp. ht.,=specific heat per pound of wiater.

q.=pounds of water per hour.[

't. r.==temperature rise of water. I, t. d.='temperature drop of airf- V The values of V eration of the meter is suchfas' to maintain the ratio e I capacity per cubic toot ofi specific'heat and Fheat. capacity being'essentially constant, the op-f lhe equation of the heat relation "would constant, so'that the quantity of water flowing is a direct measure of the quantity "at 12.5 degrees F. temperature drop of the air-and 62.5 degrees F. temperature rise of the water. I c

As will be apparent to those skilled in the art, the necessity formeters' l3 and 18 may be eliminated and the rate of flow of air in conduit 5 measured-by providing a constant flow of water, and utihzing the galvanometer element 19 for balancing the bridge through. a slide-wire rheostat,-in which case the device would Vmeasure the variable ratio between the temperature rise of the Water and thetemperature drop of the air; whereasthe rate :of flow of air could be indicated and recorded directly by said element upon a suitably calibrated movingchart'or the'lilre. g

While I have particularly described the illustrated device as adapted for the measurement of the rate of fl ow' of heated air by effecting a heat exchange between the sameand a flow of cooling water, it is to be understood that any desired fluids may be utilized in the respective flows, provided there is a substantial difference in the temperatures thereof prior to the heat exchange;

What I claim and desire to secure by Letters Patent is: v

1. In a method of ascertaining the rate of flow of a fluid, the steps which comprise causing a heat transfer between the flowing fluid and a fluid medium so that there are three factors involved, the temperature chan e of said fluid the tem ieraturechan' 'e of the fluid medium and the quantity of fluid medium, maintaining onlyxa predeter mined ratio between the values of such temperature changes irrespective of relatively wide variations in such values per se, and

measuring the quantity of said fluid mes chum.

2. Themethod of measuring a flow of fluid, which comprises effecting a heat transfer between the flowing fluid and a flowing medium, utilizing the effect of relative changes in temperatures of vsaid fluid and said medium as a result of the heat transfer to so proportion the relative rates of flow of said fluid and said medium as to maintain only a predetermined proportionality between the temperature changes thereof due to the heat transfer under conditions of relatively wide variations in the values of such temperature changes per se measuring the flow of said medium, and utilizing the value so ascertained as a direct measure of 'the flow of said fluid.

3. Apparatus for measuring the rate of flow ofa fluid, comprising a conduit through which the fluid to be measured flows, means for effecting aflow of fluid medium in heat exchanging relationwith the fluid in said conduit, means for-automatically determining the relative changes in temperatures of said fluid and said'fluid medium as a result of the heat transfer, said last mentioned meansincluding means for automatically varying the rate of flow of said fluid medium for providing only a constant ratio of the temperature changes of i said flui-d'and said fluid medium due to the heat transfer irrespective of relatively wide variations in the values of such temperature changes per se, and means controlled by-the rate of flow of said fluidmedium for direct ly, indicating the rate of flow of saidfluid.

4. The combination with a plurality of conduits'for effectin passage of separate fluids in heat exchanging relation with each other, of thermometer resistances of equal value at the lnlet and ex1t ends respectively of one of said conduits, thermometer. resistances of equal value at the inlet and "exit ends respectively of another of'said conduits, means forconnecting said inlet thermometer resistances to form one arm ofa WVheatstone bridge, means for connecting said .exit thermometer resistances to form another arm of said bridge, a balancing resistance interposed between said first-mentioned inlet thermometer resistance and said second-mentioned exit thermometer resist ance, andmeans controlled by said bridge for maintaining the latter in substantially balanced condition, said means including means for varying the rate of flow of one of said fluids tothereby maintain a predetermined proportionality between the temperature differences of the respective fluids as a result of the heat transfer. v 5. The combination with a plurality of "conduits for effecting passage of separate fluids in heat exchanging relation with each other, of thermometer resistances of equal value at the inlet and exit ends respectively of one of said conduits, thermometer-resistances of'egual value at the inlet and exit ends. respectively of another of said con-.-

duits, means for connecting said inlet thermometer resistances to form one arm of a Wheatstone bridge, means for connecting said exit thermometer resistances to form another arm of saidbridge, a balancing resistance interposed between said inlet; ther- .mometer resistances and said exit thermometer resistances, means controlled by said bridge for automatically varying the rate of flow of one of said fluids whereby said bridge is malntained in substantially balanced condition, and" means for utilizing I the rate of flow f said last mentioned fluid as a directindication oli therate of flow of the other of said fluids. V a V v 6. The comb nation with a. pair oi conv duits for effecting passage; of separate fluids in heat exchangingrelation With each other,

0f thermometer resistances of equal value at the inlet and exit endsrespectively of one of said conduits, thermometerresistances of equal value at the inlet and exit ends respece tively of another of said conduits, means for connecting said inletthermometer resistances to form one arnroi a lVheatstone bridge, means for connecting said exit thernometer resistances to :torni another arm of said bridge, means for initially balancing 7 said bridge, means controlledby said bridge for automatically maintaining the latter in substantiallybalanced condition, said means including means ior varying therate of flow of one of SELlClfflLlidS to thereby maintain a predetermined proportionality between the temperature differences of the respective fluids as a result-of the heat exchange, and means tor directly measuring the flow ct said one of saidfluids. v

7. The combination .With a pairv 0t conduits for efliectingpassage of separate fluids in heat exchanging relation with each other,

vof thermometer resistances of equal value at the inlet and exit ends respectlvely of one of said conduits, thermometer resistances 0:"

equal Value at the inlet and exit ends respectively of the other of said conduits, means tor connecting sa d inlet thermometer re- 'sistances to form one arm of a VVh'eatstone bridge, means for connecting saidexit thermometer resistances to' form another arm 0t said bridge, means for initially balancing said \Vheatstone bridge, means controlled by relation ith said fluid, individual ther inometer resistances in the respective conduits to be subjected to the thermal effects of said fluid and said medium priorto the heat exchange, like thermometer resistances in the respective conduits to be subjected to the" thermal effects-of said fluid and said medium alter. the heat exchange, means for connecting said first mentioned resistances in series as one leg of a VVheatstone bridge,

bridge, a pair of equal resistances forming the other legs of said bridge, and means for automatically effecting and maintaining a substantially balanced condition of said bridge, said means comprising an electrothe flow of said medium and a galvanometer device connected across said bridge and adapted to'control the operation of saidvalve. I s

means for connecting said second mentioned resistances inseries as another leg 01: sa d" -magnetically operated valve for controlling I 1 In Witness whereof, I have hereunto subv scribed my name.

CLARENCE s. PINKERTON.

said bridge for maintaining the latter in' substantially balanced condition, said means includin means for var in the-rate of flow of one of said fluids to thereby maintain a predetermined proportionality between the temperature diiierences of the respective fluids as a result oi the heat exchange, and

- means for measuring-the flow of said one of said fluids, said means being calibrated to indicate directly the flow of the other of said V I fluids. r r

' 8.'A fluid meter comprising .a conduit 7 through Which astream of the fluid to be measured vflows, means :tor effecting a heat exchange between said fluid and a flowing subjected to the temperatures of said fluid and said medium before and after said heat exchange, said means ncluding means to automatmally vary'the-rate of flowoit said medium to maintain only a constant propor t onalityvbetween the temperature change of said fluid and the temperature change of said medium resulting from the heat transfer and irrespective of relativelyvwide varimeeium, and associated means respectively 

